On June 19, 1787, the framers of the U.S. Constitution decided that the term of a senator should run for seven years. They also tentatively agreed that House members should serve three years, that Congress should elect the president, that the president should serve for a term equal to that of a senator, and that the Senate should appoint Supreme Court justices. Obviously, the framers had a lot of work ahead of them over the following three months to shape the delicately balanced Constitution we know today.

Why a seven-year term for senators? Members of the existing Congress under the Articles of Confederation—a unicameral body—served one-year terms. In deciding to create a bicameral Congress to replace that moribund institution, the Constitution's framers recognized that the Senate, chosen by state legislatures, would be a smaller body than the popularly elected House. To avoid being unduly threatened by public opinion, or overwhelmed by the House's larger membership, senators would need the protection of longer terms.

The framers looked to the various state legislatures for models. Although the majority of states set one-year terms for both legislative bodies, several established longer tenures for upper house members. Delaware had three-year terms with one-third of its senate's nine members up for election each year. New York and Virginia state senators served four-year terms. Only Maryland's aristocratic senate featured five-year terms, making this legislative body the focus of the Constitutional Convention's Senate term debates.

Framers either praised Maryland's long terms for checking the lower house's populist impulses, or feared them for the same reason. Some convention delegates believed that even five-year U.S. Senate terms were too short to counteract the dangerous notions likely to emerge from the House of Representatives.

James Madison first supported the seven-year term but then raised it to nine, so that one-third of the Senate seats could be renewed every three years. Others thought that was too long. On June 26, the convention compromised on the six-year term, with a two-year renewal cycle. None of this pleased New York Delegate Alexander Hamilton, who believed that the only protection for senators against the "amazing violence and turbulence of the democratic spirit" would be terms lasting a lifetime.